The invention relates to an arrangement in connection with a coating line which comprises a fibre payout device from which fibres are arranged to be guided to a press for forming a coating round the fibres, a cooling device for cooling a conductor formed by the coating and the fibres, a pulling device by means of which the conductor formed by the coating and the fibres is pulled further from the press, and means for guiding the conductor to the next processing stage after the cooling, whereby the pulling device is arranged above the height of the line so as to enable the lowest point of the pulling device to be substantially at the height of the line.
In fibre cable production, a common requirement at present is that excess fibre lengths can be kept to the minimum. A common principle in the field is that a desired excess fibre length is produced by winding a conductor formed by a sheath and a fibre or fibres round a wheel of a determined diameter, whereby the fibres are pressed against the inner surface of the sheath, and a negative excess fibre length is formed between the sheath and the fibres. At the next processing stages, the sheath contracts as a result from the cooling, whereby a final, usually positive excess fibre length with respect to the sheath can be achieved for the fibres.
At present, arrangements of this kind are widely known in connection with secondary coating lines of optic cables, for example. In the field, it is known to use a wheel drive device or a belt drive device as a pulling device. U.S. Pat. No. 4,893,998 and EP publications 0 286 819 and 0 275 994 disclose solutions which can be given as examples of known solutions in the field. In these solutions, the pulling device is positioned below the fibre line and mounted to be a fixed part of the production line.
In a common one-wheel pulling device, a product paid out from a press must be wound round a pulling wheel once or twice, and therefore the product must be deviated from the wire line by appropriate controllers. The controllers, however, generate friction and scratch the surface of the sheath. The friction generated by the controllers leads to the fact that line rates cannot be increased since an increase in the rate increases the frictional forces too much. To place the pulling device below the fibre line is usually also technically difficult and a structure fixedly mounted in the line makes the start-up of the line more difficult since the product paid out from the press must be passed via the pulling device. The fixedly positioned structure in the line restricts the adaptation of the production line for different processes.
Solutions in which the pulling device is positioned above the fibre line have been provided for eliminating the problems described above. EP publication 0 443 701 discloses a structure which exemplifies such a solution. However, the disadvantages presented by this known structure include all the above drawbacks of the one-wheel pulling device. Furthermore, a further drawback also presented by this solution is the difficult stage at which the product is passed via the pulling device during the start-up of the line.
An object of the invention is to provide an arrangement by means of which the disadvantages of the prior art can be eliminated. This is achieved by the arrangement of the invention, which is characterized in that the pulling device is arranged to be uplifted entirely above the height of the line substantially in a vertical direction.
A particular advantage of the solution of the invention is that the passing stage during the start-up of the line previously known to be difficult and laborious can now be performed most advantageously, in other words, it is extremely easy for the operator to guide the sheath paid out from the press to the pulling device after the pulling device has been uplifted from a groove which serves as a cooling device. A further advantage of the invention is that the invention can be extremely advantageously applied so as to enable high rates to be used on the line. A still further advantage of the invention is that the cooling and heating of the sheath can be implemented highly advantageously since the pulling device is placed in a wet space. Another advantage of the invention is that the location of the pulling device can be advantageously changed as required by the process.